Have all trace points emit to ETW.

base/debug/trace_event_win.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file contains the Windows-specific declarations for trace_event.h.
 #ifndef BASE_DEBUG_TRACE_EVENT_WIN_H_
 #define BASE_DEBUG_TRACE_EVENT_WIN_H_
 
 #include <string>
 
 #include "base/base_export.h"
 #include "base/debug/trace_event.h"
+#include "base/memory/ref_counted.h"
 #include "base/win/event_trace_provider.h"
 
 // Fwd.
 template <typename Type>
 struct StaticMemorySingletonTraits;
 
 namespace base {
 namespace debug {
 
 // This EtwTraceProvider subclass implements ETW logging
 // for the macros above on Windows.
 class BASE_EXPORT TraceEventETWProvider : public base::win::EtwTraceProvider {
  public:
   // Start logging trace events.
   // This is a noop in this implementation.
   static bool StartTracing();
 
-  // Trace begin/end/instant events, this is the bottleneck implementation
-  // all the others defer to.
+  // Trace begin/end/instant events.
   // Allowing the use of std::string for name or extra is a convenience,
   // whereas passing name or extra as a const char* avoids the construction
   // of temporary std::string instances.
   // If -1 is passed for name_len or extra_len, the strlen of the string will
   // be used for length.
   static void Trace(const char* name,
                     size_t name_len,
                     char type,
                     const void* id,
                     const char* extra,
                     size_t extra_len);
 
   // Allows passing extra as a std::string for convenience.
   static void Trace(const char* name,
                     char type,
                     const void* id,
                     const std::string& extra) {
     return Trace(name, -1, type, id, extra.c_str(), extra.length());
   }
 
   // Allows passing extra as a const char* to avoid constructing temporary
   // std::string instances where not needed.
   static void Trace(const char* name,
                     char type,
                     const void* id,
                     const char* extra) {
     return Trace(name, -1, type, id, extra, -1);
   }
 
+  // Emit a trace event.
+  // The event is defined by |category_group|, |name| and |type|.
+  // |id| helps to identify related events.
+  // |num_args| indicates the number of custom arguments to add to the trace.
+  // It must be <= |kTraceMaxNumArgs|. The names of the arguments are specified
+  // in |arg_names|. |arg_types| indicates how to interpret the value of
+  // each argument. Finally, the value of an argument is obtained from
+  // |convertable_values| if its type is TRACE_VALUE_TYPE_CONVERTABLE,
+  // from |arg_values| otherwise.
+  static void TraceWithArgs(
+      const char* category_group,
+      const char* name,
+      char type,
+      unsigned long long id,
+      int num_args,
+      const char** arg_names,
+      const unsigned char* arg_types,
+      const unsigned long long* arg_values,
+      const scoped_refptr<ConvertableToTraceFormat>* convertable_values);
+
   // Retrieves the singleton.
   // Note that this may return NULL post-AtExit processing.
   static TraceEventETWProvider* GetInstance();
 
   // Returns true iff tracing is turned on.
   bool IsTracing() {
     return enable_level() >= TRACE_LEVEL_INFORMATION;
   }
 
+  // Exposed for unittesting only, allows resurrecting our
+  // singleton instance post-AtExit processing.
+  static void Resurrect();
+
+ private:
+  // Ensure only the provider can construct us.
+  friend struct StaticMemorySingletonTraits<TraceEventETWProvider>;
+  TraceEventETWProvider();
+
   // Emit a trace of type |type| containing |name|, |id|, and |extra|.
   // Note: |name| and |extra| must be NULL, or a zero-terminated string of
   //    length |name_len| or |extra_len| respectively.
-  // Note: if name_len or extra_len are -1, the length of the corresponding
-  //    string will be used.
+  // The event format consists of:
+  // The "name" string as a zero-terminated ASCII string.
+  // The id pointer in the machine bitness.
+  // The "extra" string as a zero-terminated ASCII string.
+  // Optionally the stack trace, consisting of a DWORD "depth", followed
+  //     by an array of void* (machine bitness) of length "depth".
   void TraceEvent(const char* name,
                   size_t name_len,
                   char type,
                   const void* id,
                   const char* extra,
                   size_t extra_len);
 
-  // Exposed for unittesting only, allows resurrecting our
-  // singleton instance post-AtExit processing.
-  static void Resurrect();
-
- private:
-  // Ensure only the provider can construct us.
-  friend struct StaticMemorySingletonTraits<TraceEventETWProvider>;
-  TraceEventETWProvider();
+  // Emit a trace event.
+  // The event format consists of:
+  // The "name" as a zero-terminated ASCII string.
+  // A 64 bits "id" to help identify related events.
+  // The "category" as a zero-terminated ASCII string.
+  // For each extra argument, a "name" followed by a "value", both
+  //     zero-terminated strings.
+  // Optionally the stack trace, consisting of a DWORD "depth", followed
+  //     by an array of void* (machine bitness) of length "depth".
+  void TraceEventWithArgs(
+      const char* category_group,
+      const char* name,
+      char type,
+      unsigned long long id,
+      int num_args,
+      const char** arg_names,
+      const unsigned char* arg_types,
+      const unsigned long long* arg_values,
+      const scoped_refptr<ConvertableToTraceFormat>* convertable_values);
 
   DISALLOW_COPY_AND_ASSIGN(TraceEventETWProvider);
 };
 
 // The ETW trace provider GUID.
 BASE_EXPORT extern const GUID kChromeTraceProviderName;
 
-// The ETW event class GUID for 32 bit events.
+// The ETW event class GUID for old events from TRACE_EVENT_*_ETW macros.
 BASE_EXPORT extern const GUID kTraceEventClass32;
 
-// The ETW event class GUID for 64 bit events.
-BASE_EXPORT extern const GUID kTraceEventClass64;
-
 // The ETW event types, IDs 0x00-0x09 are reserved, so start at 0x10.
 const base::win::EtwEventType kTraceEventTypeBegin = 0x10;
 const base::win::EtwEventType kTraceEventTypeEnd = 0x11;
 const base::win::EtwEventType kTraceEventTypeInstant = 0x12;
 
-// If this flag is set in enable flags
+// Enable flags that can be set for the trace session.
 enum TraceEventETWFlags {
+  // Include a stack trace for each event.
   CAPTURE_STACK_TRACE = 0x0001,
+
+  // Include simple arguments with traced events.
+  CAPTURE_SIMPLE_ARGUMENTS = 0x0002,
+
+  // Include all arguments with traced events. Some arguments can be quite
+  // large. Tracing them adds an overhead that can affect performance.
+  CAPTURE_ALL_ARGUMENTS = 0x0004
 };
 
-// The event format consists of:
-// The "name" string as a zero-terminated ASCII string.
-// The id pointer in the machine bitness.
-// The "extra" string as a zero-terminated ASCII string.
-// Optionally the stack trace, consisting of a DWORD "depth", followed
-//    by an array of void* (machine bitness) of length "depth".
-
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_TRACE_EVENT_WIN_H_